the book is called "the price of civilization". a conversation with professor jeffrey sachs coming up right now. >> there is a saying that dr. king had that said there is always the right time to do the right thing. i try to live my life every day by doing the right thing. we know that we are only halfway to completely eliminating hunger and we have work to do. walmart committed $2 billion to fighting hunger in the u.s. as we work together, we can stamp hunger out. >> and by contributions to your pbs station from viewers like you. thank you. tavis: please welcome jeffrey sachs back to this program. he is one of the most important voices in our time. the director of the earth institute at columbia. his latest book is called "the price of civilization." he joins us tonight from new york. jeffrey sachs, good to have you back on this program. >> good to be back on. tavis: what has happened in this country since you wrote this book that made to put some new stuff in it for the paperback version? >> this book was about things really goin